Cancer of the female breast is a significant health matter worldwide. The current treatment of breast cancer includes surgery, chemotherapy and radiation therapy, as well as various combinations of these three modalities. Approximately one-half the women in the U.S. that are diagnosed with breast cancer will elect or will require a mastectomy. Thus, mastectomy procedures are commonly used for the treatment of breast cancers.
Mastectomies have been performed since the late 1800s, by a procedure commonly known as the Halstead radical mastectomy. During this procedure, the breast tissue and the pectoralis major muscle along with a variable amount of skin including the nipple-areolar complex is removed. Typically, an axillary lymph node dissection is performed concurrently with the mastectomy. This procedure leaves the patient with a Halstead radical mastectomy deformity which is disfiguring and is often emotionally traumatic. The deformity is especially disfiguring when skin grafting is required to close the defect.
The Halstead (radical mastectomy) procedure has been modified by preserving the pectoralis major muscle (a "modified radical mastectomy"), and by reducing the skin excision to allow for direct linear closure of the defect.
In the past, mastectomy closure techniques have included split thickness skin grafts attached directly to the rib cage, in the context of a Halstead radical mastectomy, or simple straight line closure of an elliptical skin excision. Closure of the skin defect could also involve the immediate incorporation of a cutaneous or myocutaneous flap to at least partially replace the resected tissue. Myocutaneous units are commonly used to cover defects, whether traumatic or post-resectional. A myocutaneous unit can be prepared as a combination of both skin and muscle, or as a muscle unit that subsequently can be skin grafted. A myocutaneous unit may be transferred as a free flap (a flap detached from its intrinsic blood supply), thereafter connecting the unit's axial blood supply to recipient vessels near the defect.
Latissimus dorsi or rectus abdominis myocutaneous flaps are the most frequently utilized myocutaneous flaps for mastectomy closure. Some common applications for latissimus dorsi flaps include coverage of defects in the head and neck area, especially defects created from major head and neck cancer resection. Other applications include coverage of chest wall defects other than mastectomy deformities. The latissimus dorsi may also be used as a reverse flap, based upon its lumbar perforators, to close congenital defects of the spine such as spina bifida or meningomyelocele.
The latissimus dorsi myocutaneous flap procedure was first combined with the Halstead mastectomy by Dr. Tansini in Italy in 1906. (Maxwell: Iginio Tansini and the Origin of the Latissimus Dorsi Musculocutaneous Flap, Plastic and Reconstructive Surgery 65(5):686-692 (1980)) As illustrated in FIG. 1, a latissimus dorsi myocutaneous flap having a cutaneous paddle P, was used to close the mastectomy defect. This myocutaneous flap has an intrinsic axial blood supply that is critical to the transfer and survivability of the flap.
Prior to the development of the Tansini procedure, random cutaneous flaps had limited survivability due to the paucity of their blood supply. The Tansini procedure did not, however, result in breast reconstruction. The flap was used only to close the chest wall defect.
Mastectomy closure techniques serve only to close the excision site. Due to the adverse characteristics of a mastectomy deformity, either from a radical mastectomy or a modified radical mastectomy, many women opt for post-mastectomy breast reconstruction. Reconstruction can take place contemporaneously with the mastectomy, or at a later time.
To achieve breast reconstruction, it is common to use a submuscular breast expander or a permanent implant in conjunction with a mastectomy closure technique. A breast expander allows for, and generally requires, sequential addition of fluid which stretches the remaining breast tissue. Accordingly, expanders or implants are inserted beneath the mastectomy incision, and have been used as a method for either immediate or delayed breast reconstruction.
There are several disadvantages to postmastectomy use of former latissimus dorsi myocutaneous flaps for excision closure or for breast reconstruction. In either of these contexts, there is always a significant transverse scar across the chest. Transverse scarring Ts is illustrated, for example in FIG. 1. The donor site scar on the back is also substantial. When such procedures are used and a breast is then reconstructed, the disadvantages are exacerbated since there is a large elliptical paddle of skin across the breast. This skin paddle has different pigmentation than the adjacent breast skin. Furthermore, the large flap of skin does not adequately recreate the contour of the breast. The resulting breast was typically malformed and flat.
Previously, major resections of skin occurred during radical or modified radical mastectomy procedures. More recently, skin resection has been limited to the nipple-areolar complex, through a circumareolar or periareolar incision. Modified radical mastectomies with circumareolar incisions have been performed on patients who did not have pre-existing invasion of the surrounding breast skin. When the skin excision is limited to the region of the nipple-areolar complex, the skin envelope of the breast is preserved.
When a circumareolar mastectomy is performed via an excision of the nipple-areolar complex, a straight line closure with insertion of breast expander has been used. (Grossman et al.: An Alternative Technique for Modified Radical Mastectomy with Immediate Reconstruction. Contemp. Surg. 38(6):20-24, (1991)) When the mastectomy and reconstruction are completed a breast expander or permanent implant is inserted, and the incision is closed with a straight line closure. Consequently, the reconstructed breast is skin deficient in comparison to the contralateral breast. This tissue shortage frequently required a repositioning surgery, with resulting scarring, on the contralateral breast.
Heretofore, a latissimus dorsi flap procedure has not contemporaneously been combined with a circumareolar mastectomy. For example, the state of the art for immediate breast reconstruction was discussed at the most recent (1992) Annual Scientific Meeting of the American Society of Plastic and Reconstructive Surgeons, in Washington D.C. Notably, when discussing the use of latissimus dorsi flaps for immediate reconstruction, this procedure was not discussed in combination with a circumareolar mastectomy. Rather, the latissimus dorsi flap was described as a myocutaneous unit with a large elliptical paddle of skin extending well beyond the boundary of the nipple areolar complex. (Van Natta: Use of the Latissimus Dorsi Myocutaneous Flag for Immediate Breast Reconstruction, oral presentation and written abstract provided Sep. 22, 1992)
Although latissimus dorsi myocutaneous flaps have not been combined with a circumareolar mastectomy, trans-rectus abdominis muscle flaps (TRAM flaps) have been used in combination with a circumareolar mastectomy. TRAM flaps serve to close a mastectomy defect and to provide breast reconstruction. With the TRAM flap a circular skin island is designed and transferred to the mastectomy defect. However, this skin island does not result in a reconstructed breast having a nipple-areolar complex with the same projection as a normal breast. In a TRAM flap procedure, the subcutaneous tissue of the flap, rather than a breast implant, fills the void left by the removal of the breast tissue. The subcutaneous tissue is primarily adipose tissue. The transferred rectus abdominis muscle functions merely as a conduit of the vascular supply. Typically, the muscular component of the TRAM flap does not serve to create a structural component of the reconstructed breast, such as a submuscular prosthetic pocket. With TRAM flaps, there is no muscular sling to be used in creating a prosthetic compartment to achieve breast volume. Rather, the majority of the reconstructed breast volume is filled by adipose subcutaneous tissue of the TRAM myocutaneous unit.
There are several disadvantages with TRAM flaps. The flap loss rate is higher, because the circulation of the myocutaneous unit is less reliable with TRAM flaps than with latissimus dorsi flaps. In many cases, a nipple-areolar reconstruction with harvesting of the patient's own areola is not possible due to the paucity of TRAM flap blood supply.
The TRAM flap is placed on top of the pectoralis muscle. Thus, an inherent disadvantage of the TRAM flap procedure is that a chest wall cancer recurrence can be covered up by this flap, which could delay the diagnosis of chest wall cancer recurrence. Since subcutaneous adipose tissue provides the majority of the reconstructed breast volume, fat necrosis of this tissue is a significant complication with this procedure. When fat necrosis of the adipose tissue occurs, calcifications and connective tissue masses can result. These sequelae can further exacerbate the difficulty of diagnosing a chest wall cancer recurrence.
In infrequent situations, the TRAM flap has been used with a pre-muscular breast prosthesis. Such pre-muscular prostheses also exacerbate the difficulty of detecting any chest wall cancer recurrence.
The donor site scar is also a significant drawback to the TRAM procedure, since it is located on the lower abdomen and runs hip to hip. Patients may also be subject to abdominal wall weakness and hernia formation as one or two rectus muscles are transferred to the breast.
The TRAM flap can be performed only once. Breast reconstruction for any subsequent breast cancer would require the use of a different technique. Furthermore, use of a TRAM flap is severely limited if the woman has any abdominal scars or if the woman has an inadequate amount of subcutaneous tissue. These limitations are especially problematic when attempting to reconstruct a large breast. Due to the involved nature of TRAM flap surgery, the procedure is often excluded for patients who have risk factors such as smoking, diabetes, or pulmonary dysfunction.
A free gluteal flap may also be designed in a similar fashion to the TRAM flap. The gluteal flap would suffer the same disadvantages as the TRAM flap, as well as the disadvantages attendant to free flaps.
In general, there are several significant drawbacks with prior breast reconstruction procedures when used in combination with a standard modified radical mastectomy. Severe scarring is one of the most serious problems. Due to the substantial contour distortion produced by these techniques, a reliable method of immediate and total breast reconstruction could not be performed, since it was difficult to determine where the nipple-areolar complex should be placed in a one-stage procedure. Thus, such procedures necessitate a multiple stage breast reconstruction that must be carried out over several months. Each subsequent procedure carries additional surgical risks, such as infection, bleeding, and anesthetic complications. After the breast is reconstructed, the resulting breast has an artificial appearance due to the large amounts of skin resection. Frequently, repositioning of the contralateral breast is required due to loss of skin on the mastectomy side.